1. Resonance excitation of single rotons in He II by an electromagnetic wave. Spectral line shape
- Author
-
V. N. Derkach, A. S. Rybalko, V. A. Tikhiy, S. P. Rubets, O. V. Usatenko, R. Golovachenko, E. Ya. Rudavskii, Sergey I. Tarapov, and Yu. M. Poluectov
- Subjects
Condensed Matter::Quantum Gases ,Physics ,Physics and Astronomy (miscellaneous) ,Liquid helium ,General Physics and Astronomy ,Neutron scattering ,Roton ,Electromagnetic radiation ,Spectral line ,Spectral line shape ,law.invention ,Momentum ,law ,Atomic physics ,Line (formation) - Abstract
The amplitude-frequency characteristic of the spectral line of electromagnetic absorption in liquid helium is measured in the frequency range 40–200GHz at temperatures in the interval 1.4–2.75K. It is found that in the roton frequency region a narrow resonance absorption line on a broad pedestal is observed. The results are compared with data on the roton spectrum found in neutron scattering experiments in liquid helium. The narrow line is due to the creation of a single roton. It is shown that the momentum conservation law is satisfied on account of the transfer of momentum to the superfluid component. The analogy of this effect with the Mossbauer effect is pointed out.
- Published
- 2009